Systems and networks for real-time monitoring of expected duration of temperature control. There are certain Phase Change Materials (“PCMs”) that have relatively high “enthalpy of fusion” (also known as “heat of fusion”). PCMs with high enthalpy are often used to preserve the temperature of some substance. This occurs, for example, when the temperature-sensitive substance is in storage, or in transit via a vehicle of some sort. Enthalpy is typically measured by equating energy of the material to internal energy plus pressure times volume, that is, H=U+pV. By measuring one or more of the characteristics of either p or V, the current enthalpy of material may be estimated, and the rate of change of the enthalpy may also be estimated.
Current methods of measuring and communicating factors for enthalpy suffer from one or more major defects, such as:                1. The package containing a PCM and or the package containing the sensitive product or material require a particular positional orientation during transit. Alterations in the transit will negatively impact the quality of measurements of the PCM.        2. There is no effective method for estimating in real-time the remaining duration of temperature control from the PCM.        3. There is no effective method for transmitting in real-time indications related to the remaining duration of temperature control from the PCM.        4. The environment of the PCM package and of the sensitive product or material is often hostile to effective communication from the PCM package to a point of information reception. For example, distance or EM interference may attenuate a signal from the PCM packaged to the point of information reception.        5. The form factor of a PCM package and package of sensitive product or material is hostile to effective communication from the PCM package to a point of information reception. For example, the form of the packages may be such that the distance between a sensor and the point of information reception is increased or blocked.        6. It is often difficult and expensive to monitor multiple PCM packages in real time.        7. Ice or dried ice is often used as a type of PCM, but due to various properties of water, measurement of the current enthalpy of the ice or dried ice, it is often difficult to monitor the remaining duration of temperature control available from the PCM material.        
There is therefore a need for various systems and methods that will overcome or ameliorate one or more of the aforementioned difficulties in measuring and communicating factors for enthalpy.